The invention is concerned with the compounds of formula (I): and salts thereof, wherein X, Y, Z, R1, R2, R3, R3&prime；, R4, R5 and R6 are defined in the detailed description and claims. In addition, the present invention relates to methods of manufacturing and using the compounds of Formula (I) as well as pharmaceutical compositions containing such compounds. The compounds may be useful in treating diseases and conditions mediated by TRPA1, such as pain.
